As filed with the Securities and Exchange Commission on August 23, 2021

Registration No. 333-                

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Adagio Therapeutics, Inc.

(Exact name of Registrant as specified in its charter)

303 Wyman Street, Suite 300

Waltham, MA 02451

(Address of principal executive offices) (Zip code)

2020 Equity Incentive Plan

2021 Equity Incentive Plan

2021 Employee Stock Purchase Plan

(Full title of the plans)

Tillman U. Gerngross

Chief Executive Officer

Adagio Therapeutics, Inc.

303 Wyman Street, Suite 300

Waltham, MA 02451

(Name and address of agent for service)

(603) 252-2274

(Telephone number, including area code, of agent for service)

Copies to:

Divakar Gupta

Ryan Sansom

Courtney M.W. Tygesson

Cooley LLP

55 Hudson Yards

New York, NY 10001

Telephone: (212) 479-6000

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  ☐

CALCULATION OF REGISTRATION FEE

PART I

INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

The information specified in Item 1 and Item 2 of Part I of Form S-8 is omitted from this Registration Statement. The documents containing the information specified in Part I of Form S-8 will be delivered to the participants in the plans covered by this Registration Statement as specified by Rule 428(b)(1) under the Securities Act of 1933, as amended (the “Securities Act”).

PART II

The following documents filed by Adagio Therapeutics, Inc. (the “Registrant”) with the Securities and Exchange Commission (the “Commission”) are incorporated by reference into this Registration Statement:

(a) The Registrant’s prospectus dated August 5, 2021 filed pursuant to Rule 424(b) under the Securities Act relating to the Registration Statement on Form S-1 (File No. 333-257975), which contains audited financial statements for the Registrant’s latest fiscal year for which such statements have been filed;

(b) The Registrant’s Current Reports on Form 8-K (File No. 001-40703) filed with the Commission on August 10, 2021 to the extent the information in such report is filed and not furnished; and

(c) The description of the Registrant’s Common Stock contained in the Registrant’s Registration Statement on Form 8-A filed on August 3, 2021 (File No. 001-40703) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), including any amendment or report filed for the purpose of updating such description.

All documents, reports and definitive proxy or information statements filed by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act (other than Current Reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits furnished on such form that relate to such items) on or after the date of this Registration Statement and prior to the filing of a post-effective amendment to this Registration Statement that indicates that all securities offered hereby have been sold or that deregisters all securities then remaining unsold shall be deemed to be incorporated by reference in this Registration Statement and to be part hereof from the date of filing of such documents. Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any subsequently filed document that also is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

Not applicable.

Not applicable.

Section 145 of the Delaware General Corporation Law authorizes a court to award, or a corporation’s board of directors to grant, indemnity to directors and officers in terms sufficiently broad to permit such indemnification under certain circumstances for liabilities, including reimbursement for expenses incurred, arising under the Securities Act. The Registrant’s amended and restated certificate of incorporation provides that the Registrant will indemnify our directors to the maximum extent permitted by the Delaware General Corporation Law, and the Registrant’s amended and restated bylaws provide that the Registrant will indemnify its directors and permits the Registrant to indemnify its officers, employees and other agents, in each case to the maximum extent permitted by the Delaware General Corporation Law.

The Registrant has entered into indemnification agreements with its directors and officers, whereby it has agreed to indemnify its directors and officers to the fullest extent permitted by law, including indemnification against expenses and liabilities incurred in legal proceedings to which the director or officer was, or is threatened to be made, a party by reason of the fact that such director or officer is or was a director, any action taken or inaction by such director or officer while acting as a director or officer, or the fact that such director or officer is or was serving at the request of the Registrant as a director, trustee, general partner, managing member, officer, employee, agent or fiduciary of any other entity, provided that such director or officer acted in good faith and in a manner that the director or officer reasonably believed to be in, or not opposed to, the best interest of the Registrant and, with respect to any criminal action or proceeding, had no reasonable cause to believe that his or her conduct was unlawful. At present, there is no pending litigation or proceeding involving a director or officer of the Registrant regarding which indemnification is sought, nor is the registrant aware of any threatened litigation that may result in claims for indemnification.

The Registrant maintains insurance policies that indemnify its directors and officers against various liabilities arising under the Securities Act and the Exchange Act that might be incurred by any director or officer in his or her capacity as such.

Certain of the Registrant’s non-employee directors may, through their relationships with their employers, be insured and/or indemnified against certain liabilities incurred in their capacity as members of the Registrant’s board of directors.

Not applicable.

Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to section 13 or section 15(d) of the Exchange Act that are incorporated by reference in the registration statement.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Waltham, Commonwealth of Massachusetts, on this 23rd day of August, 2021.

POWER OF ATTORNEY

KNOW ALL BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Tillman U. Gerngross, Ph.D., and Jane Pritchett Henderson, and each of them, as his or her true and lawful agents, proxies and attorneys-in-fact, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to (i) act on, sign and file with the Securities and Exchange Commission any and all amendments (including post-effective amendments) to this registration statement together with all schedules and exhibits thereto and any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended, together with all schedules and exhibits thereto, (ii) act on, sign and file such certificates, instruments, agreements and other documents as may be necessary or appropriate in connection therewith, (iii) act on and file any supplement to any prospectus included in this registration statement or any such amendment or any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended, and (iv) take any and all actions which may be necessary or appropriate to be done, as fully for all intents and purposes as he might or could do in person, hereby approving, ratifying and confirming all that such agent, proxy and attorney-in-fact or any of his substitutes may lawfully do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

Exhibit 5.1

Divakar Gupta

T: +1 212 479 6474

dgupta@cooley.com

August 23, 2021

Adagio Therapeutics, Inc.

303 Wyman Street, Suite 300

Waltham, MA 02451

Ladies and Gentlemen:

We have represented Adagio Therapeutics, Inc., a Delaware corporation (the “Company”), in connection with the filing by the Company of a Registration Statement on Form S-8 (the “Registration Statement”) with the Securities and Exchange Commission covering the offering of up to 36,417,895 shares (the “Shares”) of the Company’s Common Stock, par value $0.0001 per share (the “Common Stock”), consisting of (i) 16,793,090 shares of Common Stock issuable pursuant to the Company’s 2020 Equity Incentive Plan, as amended (the “Existing Plan”), (ii) 18,282,032 shares of Common Stock issuable pursuant to the Company’s 2021 Equity Incentive Plan (the “New Plan”), and (iii) 1,342,773 shares of Common Stock issuable pursuant to the Company’s 2021 Employee Stock Purchase Plan (together with the Existing Plan and the New Plan, the “Plans”).

In connection with this opinion, we have examined and relied upon (a) the Registration Statement and the related prospectuses, (b) the Company’s Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws, each as currently in effect, (c) the Plans, and (d) originals or copies certified to our satisfaction of such records, documents, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies thereof, the accuracy, completeness and authenticity of certificates of public officials, and the due authorization, execution and delivery of all documents by all persons other than the Company where authorization, execution and delivery are prerequisites to the effectiveness thereof. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.

Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state securities law, rule or regulation.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold and issued in accordance with the Plans, the Registration Statement and the related prospectuses, will be validly issued, fully paid and nonassessable (except as to shares issued pursuant to certain deferred payment arrangements, which will be fully paid and nonassessable when such deferred payments are made in full).

Cooley LLP 55 Hudson Yards, NY 10001

Phone: (212) 479-6000 Fax: (212) 479-6275 Cooley.com

Adagio Therapeutics, Inc.

August 23, 2021

Page Two

We consent to the filing of this opinion as an exhibit to the Registration Statement.

Sincerely,

Cooley LLP 55 Hudson Yards, NY 10001

Phone: (212) 479-6000 Fax: (212) 479-6275 Cooley.com

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of Adagio Therapeutics, Inc. of our report dated May 21, 2021, except for the effects of the stock split discussed in Note 15 to the consolidated financial statements, as to which the date is August 2, 2021, relating to the financial statements of Adagio Therapeutics, Inc., which appears in Adagio Therapeutics, Inc.’s Amendment No. 1 to the Registration Statement on Form S-1 (No. 333-257975).

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts

August 23, 2021